The Crag Fiend

Boss fight starts at 1:10 I didn't engage with the free items given at the start since I wanted to gauge how strong it would be in normal dungeon delving. I assume they make the fight easier since the tooltip says it stuns or something. Also yes, it took me until round 4 to realize I can't use Celestial Javelin vs Rank 1 or 2. I am so good at this game.